import {lineNumberFor} from "../line/utils_line.js"
import {compensateForHScroll} from "../measurement/position_measurement.js"
import {elt} from "../util/dom.js"

import {updateGutterSpace} from "./update_display.js"

// Re-align line numbers and gutter marks to compensate for
// horizontal scrolling.
export function alignHorizontally(cm) {
    let display = cm.display, view = display.view
    if (!display.alignWidgets && (!display.gutters.firstChild || !cm.options.fixedGutter)) return
    let comp = compensateForHScroll(display) - display.scroller.scrollLeft + cm.doc.scrollLeft
    let gutterW = display.gutters.offsetWidth, left = comp + "px"
    for (let i = 0; i < view.length; i++) if (!view[i].hidden) {
        if (cm.options.fixedGutter) {
            if (view[i].gutter)
                view[i].gutter.style.left = left
            if (view[i].gutterBackground)
                view[i].gutterBackground.style.left = left
        }
        let align = view[i].alignable
        if (align) for (let j = 0; j < align.length; j++)
            align[j].style.left = left
    }
    if (cm.options.fixedGutter)
        display.gutters.style.left = (comp + gutterW) + "px"
}

// Used to ensure that the line number gutter is still the right
// size for the current document size. Returns true when an update
// is needed.
export function maybeUpdateLineNumberWidth(cm) {
    if (!cm.options.lineNumbers) return false
    let doc = cm.doc, last = lineNumberFor(cm.options, doc.first + doc.size - 1), display = cm.display
    if (last.length != display.lineNumChars) {
        let test = display.measure.appendChild(elt("div", [elt("div", last)],
            "CodeMirror-linenumber CodeMirror-gutter-elt"))
        let innerW = test.firstChild.offsetWidth, padding = test.offsetWidth - innerW
        display.lineGutter.style.width = ""
        display.lineNumInnerWidth = Math.max(innerW, display.lineGutter.offsetWidth - padding) + 1
        display.lineNumWidth = display.lineNumInnerWidth + padding
        display.lineNumChars = display.lineNumInnerWidth ? last.length : -1
        display.lineGutter.style.width = display.lineNumWidth + "px"
        updateGutterSpace(cm.display)
        return true
    }
    return false
}
